Flight Changi Airport departs from Singapore Changi Airport at 16:00 and arrives at Chengdu Chengdu Shuangliu International Airport at 20:25.
The flighttime is about 5h 25m. The distance travelled ("as the bird flies"): 776 Km. So the average speed is roughly 143 Km.
There is an 1 hour time difference between Singapore and Chengdu